Removing splotches in Vray Render
polycounter lvl 6
Hey guys I will be doing a large Vray render (5/6k) of the following 2 images to be printed and Im noticing some bad splotches already in the smaller versions. Does this fall under light subdivisions or a GI problem?
Replies
http://docs.chaosgroup.com/pages/viewpage.action?pageId=7897184#
@eric It seems my solution would be to select Adaptive Subdivision Sampler rather than Adaptive DMC with a max subdiv level of 3/4. Would that be correct?
Flower Setup
Fish Setup
Also try to activate subpixel mapping, helps with light artefacts when you don't want to add 50000 samples and bake for 15 hours.
First off turn off anti aliasing, it's not like game anti aliasing where it cleans up jaggies it's almost just a sharpen in Photoshop.
Now to set up your DMC sampler settings. go to your render elements tab and add a "sample rate" and render again. This is going to show you a heat map of how much work your DMC sampler has to do. your image sampler is pretty much your render quality settings so getting this part right is crucial.
once your render finishes check out your sample rate in the vray frame buffer.
You'll get this, basically you want your image sampler to work less and only in the right places. Firstly increase your high subdiv number to 24 (i'll explain in a second) you can make it work less by increasing the threshold number from 0.01 (this is crazy high by the way) to anything between 0.01 to 0.2. This number controls the difference between each pixel. if the brightness of any colour (RG or
now your high subiv settings in your image sampler is also way to low. Those red spots are so you how many samples it's using to clean up your image, for example the red spots are using the highest number you set (24) and the blue will be using the lowest (1) since we added a number of 24 your going to have 24 colors going from blue to red in your sample rate render element. in your first settings you only had 4, your limiting vray to much with that. it needed more samples to do what your asking of it with a threshold of 0.01. it's like asking someone to paint you a picture but not giving them enough paint to really do it. your getting wishy washing image sampling.
play around with the high sub div number until the red spots are like the image above, only in the places of highest contrast (you do want these red spots by the way so don't just type in 200 and move on :P)
Now your splotches are caused by your GI. I could just say in your irradiance map settings change your interp samples to 50 and be done with it but I'm going to just give you better settings for it all
Change your second bounce pass to light cache. Brute force is slow, inefficient and full of noise, its really only meant to be used by those who can mange it properly. almost like a pro mode or something.
in your irradiance map settings lower the pre set to medium and up the interp samples to 50 and the subdivs to 80. your giving it a higher sample rate (more rays, smaller splotches) and the interp samples number tells vray how it can blend those rays together, lower number more splotchy but sharp lighting, higher number more blurry lighting but less splotchy. its another balancing act. in your render elements tab as a raw total lighting element to see just the lighting by its self.
That should do it :poly142:
EDIT:
oh and increase yoursub divs on each light to around 200
Thank you for your help so far. Below are the settings for the render:
Tiny render below
I'm on an older version of max and vray but just use these settings.